Laparoscopic surgery at this time is well known. Instead of making large incisions in the body of the patient, many operations are carried out by use of a laparoscope. A laparoscope enters the abdominal cavity by way of a small hole through the skin and underlying tissues, generally through a cannula and trocar assembly. The trocar generally comprises a sharpened tubular instrument that simply punches through the skin and underlying tissue. The laparoscope has a fiber optic bundle for carrying light into the working area within the body, and optical means, generally comprising a series of lenses, for viewing the interior of the body. The viewing may be direct by the surgeon's eye at the exit end of the laparoscope, or it may have an electronic device at the exit end for sending signals to a monitor where the operative area can be viewed on an enlarged screen.
In order to provide adequate working and viewing room laparoscopic surgery generally is accomplished by insufflation of the interior of the body with a gas under pressure. Carbon dioxide is the preferred gas, since it is easily accommodated by the body, and is inexpensive. The gas may be supplied initially from pressurized tanks or bottles, and distributed to the laparoscope by an insufflator. After use, the gas passes from the body, and preferably is delivered to the hospital evacuation system.
The object lens of the laparoscope is obviously exposed to the interior of the body in which the surgery is being accomplished by a small diameter, remotely operable tool or device. Such a tool or device often includes a cauterization device which burns tissue and generates smoke, and may also sputter bits of tissue into the interior of the body. The tissue and smoke may for the object lens of the laparoscope, hindering visibility of the site of the operation. Another cause of fogging is condensation of moisture onto the cold lens surface.
Some progress has been made in the production of a laparoscope with means for removing image impeding material from the object lens. However, this does nothing for the thousands of laparoscopes now in the field. Such a laparoscope is disclosed in Auhll U.S. Pat. No. 5,207,213.